The chief yellow pigment of Tibetan painters was orpiment, a natural yellow trisulfide of arsenic, AS2S3' Deposits of orpiment occur near the surface of the earth, especially near hot springs or in the vicinity of silver deposits. In Tibet the most famous deposits were found in East Tibet, near Chamdo. Large quantities of orpiment are also said to have been mined at Shihhaung- Ch'ang in Yunnan Province in China.3 7

The mineral orpiment is easily identifiable by its yellow metallic lustre and its strong sulfur-like smell. It is also very soft (1.5 - 2 on Moh's scale). There are a variety of qualities; in Tibetan painting as in Tibetan medicine the pure, intensely yellow orpiments were best, while the greenish and reddish varieties were inferior. 38 Due to its eye-catching appearance and its chemical properties (like vermilion it could be artificially produced by sublimation), in early times orpiment was the object of alchemical speculations in China and elsewhere.

Orpiment always occurs in nature together with realgar, the closely related red sulfide of arsenic. Both orpiment and realgar were formerly used in European painting, but being highly poisonous their use has actually been outlawed in many places. However, in Tibet where European synthetic yellows do not seem to have penetrated in appreciable quantities, orpiment and realgar continued to have a wide application down to recent times. Realgar, it should be added, was not commonly used in thangka painting by our Central Tibetan (dbus pa) informants. For them, its widest application was in the painting of walls and wooden surfaces.

Orpiment and realgar had certain medicinal uses in the Ayurvedic medicine of Tibet, but most painters also knew the pigments to be harmful if ingested in any quantity. Therefore, although many painters licked their brush tips while applying other pigments, most were careful not to get any of these arsenic compounds into their mouths.

When preparing orpiment for use as a pigment, the artists ground it in the dry state. It could be ground vigorously,39 but when ground extremely finely the richness of its yellow was slightly diminished.

Yellow Ochre (ngang pa)

Yellow ochre is a fine-grained earthy variety of the mineral limonite, a hydrated ferric oxide. Although ochres have been popular among Western artists for some centuries, Tibetan thangka painters seldom used them as pigments in their own right, preferring the more intense yellow of orpiment. Nevertheless, yellow ochre was widely used as the main undercoat for gold.

In Central Tibet the most highly prized yellow ochre (ngang pa or ngang sang) came from the Zhwa-lu district of Gtsang; hence the name, zhwa lu ngang pa. Because it had a very soft and earthy consistency, this pigment did not require much grinding. In fact, one painter stated that instead of grinding it in a mortar, he used to soak it in water and then use his fingers to rub off the smooth, clay-like outer layers that had become saturated and soft.

The related earth colour red ochre (btsag) was also well known in Tibet. Chemically, red ochre is identical to yellow ochre, except that the red lacks the hydrous content of the yellow. It was a cheap pigment that was often employed like whitewash for painting the outside of large buildings. Red ochre too was not widely used in thangka paintings in recent times. Investigations of older paintings, however, have indicated its presence; in the study by Mehra red ochre showed up in five of the eight museum thangkas chosen for examination.40

Earth White (ka rag)

The main white pigments in Tibet were calcium compounds. The most common white was a mineral called ka rag, which seems to have been a high-grade white chalk. Like limestone and marble, chalk is basically calcium carbonate, but chalk is not to be confused with lime (rdo zho or rdo thai), the white oxide of calcium that is made by heating limestone in a kiln.41

In Tibet, the best known and for painting the most valuable ka rag came from Rinpung (Rin-spungs), a place roughly half way between Lhasa and Shigatse that in the 16th century was the seat of the rulers of Tibet. In parts of Tibet the fine grade of ka rag from Rinpung was quite costly; in the town of Shekar Dzong (shel-dkar rdzong) in Western Gtsang, for instance, the pigment was said to cost weight for weight as much as butter. Therefore for purposes that required a lot of white, such as the preparation of the ground, painters commonly substituted less expensive grades of white.

According to the artists there were two main varieties of the ka rag mineral: "masculine" (pho) and "feminine" (mo). The masculine type (pho rag or pho dkar) was harder and coarser, while the feminine (mo rag or mo dkar) was relatively soft and fine. However, when the masculine was left out to weather in a stream bed or in some wet place it would convert to the feminine, becoming., lighter and softer. If the artist wished to effect this change even faster, he would first soak the pho rag in water for a few days, At first the pho rag made the water turn yellow, and when this happened the discoloured water had to be poured out and replaced with fresh water. When the water stopped yellowing the mineral could be ground, and again soaked in water. The need for preliminary soaking, combined with its greater hardness while grinding, made the masculine type more work to prepare, but when finally rendered into a usable pigment it could not be distinguished from the feminine variety.

Ka rag was ground dry, and then after that even the feminine mo rag had to be soaked in water to leach out yellowing impurities. When the pigment had been well ground, the artist might test it, by putting a small drop on his tongue and then feeling for any undesirable granularity by rubbing it with his tongue against the roof of his mouth. After final grinding and soaking, ordinary earth whites as well as cheaper earth pigments were commonly transferred to earthenware pots, which through absorption and evaporation speeded up the extraction of water from the wet pigments. By contrast, Tibetan painters always stored their expensive pigments in non-porous containers.

In addition to ka rag, painters in some regions of Tibet occasionally used other calcium compounds for their white. Eastern Tibetan artists, for instance, described a white pigment that they used to make by calcining animal bones. This too was a calcium white since the main constituent of bone ash is calcium phosphate. Similar bone-ash whites were used in medieval European painting. Finally, the analysis of the pigments of one "Nepalo-Tibetan, late 15th or 16th-century" thangka revealed the presence of a white pigment made up of chalk plus gypsum.42 Gypsum is a mineral formof calcium sulfate that has been used to make whitepaints in many parts of the world since very early times.

The use of synthetic whites such as lead white and zinc white in Tibetan thangkas was not mentioned by our informants. Nevertheless, by the beginning of the present century small quantities of lead white in particular must have been coming into Tibet from India or China.43

Carbon Black (snag tsha)

The blacks used as paints in Tibet were made from carbonaceousmaterials, and the sources - soot and black ash - were common almost everywhere in one form or another. Since carbon is chemically very inert, it was the basis for permanent, excellent pigments.

Soots and black ash were produced by heating a substance such as wood or oil without causing its complete combustion. The most common way of making soot for pigment use was to burn the chosen material slowly and imperfectly; such a fire produced smoke that consisted of millions of minute black particles of ash. These tiny particles needed only to be retrieved to form the basis for a black ink or paint.

Tibetans knew the age-old process for making ink (snag tsha) from soot and glue. Mi-pham-rgya-mtsho, for instance, gave the following description of ink manufacture:

The main material is soot, which is made by burning the wood of a larch tree (larix potaninii Bata1.: thang ma sgron shing), birch bark, or other materials and by causing the flames to burn into a vessel with a net covering (?) (khog ma dra ba can). Alternatively, one may also use the soot of a butter lamp or from a torch. Also the soot from a roasting pan [may be used], but this is the worst; and [one may even use ashes of] puffballs that have been covered with mud and burned.

[To prepare ink] one adds to the above soot a boiled solution of size that has cooled and congealed to the point that it can no longer be pierced with the tongue. [The mixture] is stirred and churned again and again in a thang-rkyal container. If it dries out one should moisten it, and it should be ground by repeatedly bringing it to a pastelike consistency.

Regarding this, some people traditionally begin by grinding mica (lhang tsher) in a thang-rkyal container. Using this as their basic material, they then mix it with soot or other materials.

During or after the grinding of the ink, if one soaks [the soot paste] in a decoction of Piper longum and cardamom (?) (kakkola) [the resultant ink] will not solidify in the winter. And if one soaks it in an infusion of camphor, Peucedanum sp. (tang ku) and white sandalwood, [the ink] will not spoil in summer. If prepared with an infusion of musk and solidified bovine bile (gi wang), it will be very runny and its flow will not be interrupted.

If one adds sugar (?) (rgyal mo ka ra) and lac dye, [there results] a rich colour. If one adds infusions of cloves, lnula helenium (?) (ru rta), camphor, Melilotus suaveolens Ldb. (rgya spos), Nardostachys jatamansi DC (spang spos), shu mo za and ar nag it will have a good smell. If one pours in some decoction of black-roasted wheat and a solution of "calf blood" (?) (be khrag), it will shine with a silver glint. A decoction of Saussurea sp. (spyi bzhur) gives a dark blue hue. If one adds a clear solution made from barberry bark (skyer shun), it gives a golden colour. [The addition of] lac dye decoction yields a copper colour. Therefore mix [the above ingredients with the ground soot] according to one's desires.

If the ink does not flow freely due to its being too viscous, add a little bit of calcined alum (dar mtshur) or borax (tsha la). If it is too thin, the addition of a kernel of grain or a bean will be sufficient to make it thicker by absorbing water. [short passage on substitute binders omitted]

The way for preparing ink from soot. Lampblack gives "extensiveness" (?) [good coverage?], but it is a little difficult to pulverize. The soot of Gentiana tibetica King (kyi lee) is excellent for ease of grinding, but it is not lustrous (or, instead of 'od che, read bong che "extensive, of good coverage"?). Wood soot is excellent for grinding and it is also of "great extension". The soot of dmar chen rtse ba has good colour and is "extensive" and easily ground, yet it is a cause for spoilage [in warm weather]. Therefore, in winter the soot of dmar chen rtse ba is best. Otherwise, for good colour, ease of grinding and "extensiveness" one should mix lampblack in equal proportions with Gentiana tibetica (kyi lee) soot.

If one desires a dark blue [ink] one should add the black surface layer of some indigo dye solution and some decoction of the Saussurea sp. (spyi bzhur) plant. If one wants a light blue, add only the Saussurea sp. decoction. [Ink of a] silvery colour can be made by adding a lot of white rice decoction and ma nu ru rta (an lnula species?) decoction in equal measure, and this mixture must be ground a long time in the sun. If one wants ink of a reddish colour and lustre, it can be made by adding a little solution containing "antelope blood" (?) after the ink has been completely ground, and then grinding the mixture further in the sun without heating it over a fire. If one wants ink that is extremely black and shiny, it can be made by adding a little shellac (la chu) [to the ink]. One should only use this ink in a warm state, and should never add any cold water to it.

Whichever kind of ink one makes, for a smooth and - - ? - - (rme ba) ink, it is important to add some decoction of ma nu ru rta.

As a replacement for the size binder, the use of rice decoction by itself will yield an ink that is easy to apply, quick in drying, and not apt to spoil in warm weather. Adding a little sug-pa root solution and size will make the ink shinier. In general, it is important to grind [the ink] for a long time, and while grinding to grind in all directions and both clockwise and counterclockwise, for this will produce an ink that will not clot up during application, and that will be easy to apply, moderately black (?) (snying nyung) and shiny.44

Although a few details of the above passages are obscure, it is clear that the Tibetans had developed their ink-making technique to a high degree.

In addition, a considerable amount of good ink was also imported into Tibet from China, and among Tibetan painters such Chinese ink (rgya snag) still remains a highly favored pigment. Like Tibetan ink, the inks of China were usually made from lampblack or from soot produced by burning the wood of a coniferous tree. According to Chinese manuals the manufacture of ink in China involved a process of mixing and grinding that was a little more involved than the method described by Mi-pham-rgya-mtsho. First of all the soot, glue solution and medicinal decoctions were combined in a porcelain basin, and they were stirred to make a thick paste-like mixture. This was then kneaded by hand and formed into balls, which were next wrapped in cotton cloth and steamed. After steaming the material was pounded in a stone mortar with a wooden pestle. It was then alternately steamed and pounded for some time. When it had become flexible and homogeneous it was rolled into long strips, which were then cut into small pieces weighing about one and one-half ounces each. These small pieces were then moistened and hammered, one at a time, on a piece of iron. Finally, following the addition of musk and camphor, the smooth material was rounded, shaped, and pressed into wooden molds. These molded ink sticks only required final drying, after which they could be wrapped and then stored for later use.4 5

In addition to the Tibetan or Chinese inks made from soot, the analysis of Tibetan painting materials by Mehra also indicated the presence of some other blacks, namely bitumen (asphaltum), "carbon black" and bone black. The latter pigment, now popularly also called "ivory black," is made by charring the bones of animals. Its presence was indicated in two thangkas, one described as "lliasa style, 18th or early 19th century", and the other as "sNar-thang school, early 17th century. ,,46 None of our informants used these.

Gold (gser )

Gold, a substance recognized almost universally as a symbol of wealth and beauty, was highly prized as a pigment by both artists and patrons in Tibet. Pure gold not only possesses its own inimitable colour and lustre, but also it does not tarnish and it is extremely workable. It can be drawn into very fine wires, or it can be beaten so thin that light can pass through it. Such qualities lend themselves very well to the purposes of an artisan, for even when applied in very thin layers the reflective metal imparts to any surface the lustre and beauty of solid gold.

Tibetans used various forms of gold for artistic purposes, including gold powder (gser rdul), gold leaf (gser shog) and mercury-gold amalgam. In thangka painting, however, the artists used only a paint of finely powdered gold. Gold applied in the form of a paint was known as "cold gilt" (grang gser), as opposed to "hot gilt" (tsha gser) - gold applied by the process of mercury gilding in which the gilded object had to be heated to evaporate the mercury.

Tibetan painters prepared cold gilt paint in a number of ways, depending on which form of gold was available to them. Often they obtained it in a finely powdered state that needed only the addition of some binder to ready it for use. In Central Tibet the painters usually obtained their gold from Newar merchants in lliasa, who nearly monopolized the sale of powdered gold there. The names of some of their establishments, such as the Blue Doors East and West (sgo sngon shar nub), were known to most of the painters in the lliasa area.

The Newar gold workers kept their technique a secret. Nevertheless it is probable that their method for powdering gold had a lot in common with the technique used by Tibetans when preparing gold for the "hot" mercury gilding.47 In the latter process a small piece of solid pure gold was beaten into gold leaf, which in turn was cut into very thin strips. The thin strips were then snipped with scissors, producing tiny rectangular specks. These specks, however, were still too coarse to be used in paint, and they had to be pulverized still further by some grinding process. It was this last and crucial step in the technique that was one of the main secrets of the Newar gold workers.

Because of its plastic qualities gold cannot be ground directly like other pigments; hence the difficulties at this stage.48 Some intermediate substance, such as stone or a special liquid medium, had to be used to keep the particles of gold from adhering to each other and to the mortar and pestle. The need for such an effective grinding medium was painfully realized not many years ago by some Tibetan artists painting temple murals in Bodhnath near Kathmandu. They tried for a long time to grind a quantity of gold to the desired consistency, but only succeeded in producing a dull, dark mixture that was totally unsuitable for painting. After thus blackening about five ounces of gold, they finally went to the Newar proprietors of one of the "Blue Doors" who are still doing business in Kathmandu, and bought from them the required amount of powdered gold. (Another problem may have been that the gold was not sufficiently pure to begin with. The Newars were also experts at purifying gold).

When Tibetans did prepare their own "cold gold", they commonly used small pieces of crushed stone as their grinding intermediate. L. S. Dagyab described the basic process as follows: Small ribbon-like strips [of gold] . . . are in turn mixed with some powdered bits of stone or glass. This mixture is ground with a rounded stone and a little water is added now and then till the mixture acquires a liquid consistency like moist clay. The bits of stone and glass can then be washed out leaving the gold liquid.49

Artists in Eastern Tibet had developed a slightly more involved technique. Mi-pham-rgya-mtsh050 described the process:

[Pound] the gold into leaf that is so thin tha~ it can be cut with the fingernails. Then, thoroughly grind it in a stone [mortar] together with mkhar gong [a siliceous mineral?] .51 Next, encase the ground gold in bovine dung, and when it has dried, burn it. Gently stir the ashes in some water, and the stone powder and gold will separate. When the gold powder is very fine [but the gold ink made from it] is too runny, mix it with some nearly congealed roasted-wheat glue or grain glue52 or animal-hide glue.

Pure gold neither tarnishes nor reacts with other pigments under normal conditions. The gold used by Tibetan artisans, however, often contained darkening impurities. These could be detected by rubbing some gold powder between two clean sheets of paper. Discolouration of. the paper signified oxidation or adulterants. To obtain the brightest gold sheen the powder had to be washed before use. The artist first added a little size solution to the gold powder in a cup, and then rubbed the mixture with the thumb or fingers until it became thick and nearly congealed. Then he added a bit more size solution and repeated the stirring. After doing this two or three times the artist allowed the gold dust to settle to the bottom of the cup, and he then poured off the dirty liquid. Finally he added clear water and stirred the gold again, repeating the rinsing until the run-off water was quite clean.

If you leave this gold-powder [paint] to sit for a day, it will become [darkened] as if covered with a black film. Consequently, pour some water into [its] colour pot and thoroughly mix [the gold paint and water] with a stirring stick (shing bu), repeatedly throwing out the water which has drawn the dark contaminants into solution. Then add the correct amount of size solution. . . .53

Once the gold had been ground it could be stored as a dry powder or in the form of small discs or drops. Tibetans made "gold drops" (gser gyi thigs po) by first mixing the cleaned gold powder with some binder. Then they poured the mixture one drop at a time onto a smooth surface and allowed it to dry. If quicker drying was required, the drops could be poured onto a smooth board of unfinished wood, where they would solidify quicker since the water would both evaporate into the air and be absorbed into the wood. Gold paint in drop form was convenient for artists and was also popular among pilgrims and Buddhist devotees. In this form a pious person could conveniently offer a certain amount of gold to the face of a holy image or to some famous shrine, in much the same way that gold leaf is still offered by Buddhists in Southeast Asia.

Another way that Tibetan artists prepared gold paint (especially in more recent times in India and Nepal) was directly from gold leaf. It will be remembered that gold leaf was an intermediate stage in the preparation of gold powder from solid gold. However, modern commercially prepared gold leaf is actually so fine that an artist can convert it into paint without having to grind it with mortar and pestle.

Gold leaf could be made into gold paint by mixing the leaf in a cup with a little honey, and then rubbing the mixture against the side of the cup with the thumb.This technique, although easier than grinding specks of gold, nevertheless required a special touch because the natural tendency of the gold leaf was to clump up and not to dissipate into fine particles. To facilitate the mixing some artists said that it was best to stir the gold leaf continuously in one direction only.

Imitation Gold and Other Powdered Metals

Tibetans used several other powdered metals besides gold for art and related purposes. Powdered silver (dngu/ rdu/), for example, was regularly used (as was gold) in preparing metallic "ink" for the copying of sacred books on dark, indigo-dyed paper (mthing shog). Silver was of course much cheaper than gold. One of the problems with silver was that it was more prone totarnish and darken than gold. Silver was not widely used in thangka painting; the only time we saw silver applied to thangkas was in the paintings of the Khams-pa painter Dorje Drakpa. He employed silver in the body nimbuses of White Tanis. In the eyes of Tibetan artists and patrons, silver could never be a real rival to gold.

Other metals were also powdered and used as pigments by Tibetan artisans, but only seldom were they applied to thangkas in Tibet. Mi-pham-rgya-mtsho, for instance, gave directions for the powdering of brass and copper to make metallic paints.54 If these powdered metals were used in thangkas it was only as imitation golds. One or two of our teachers mentioned the use of imitation golds by thangka painters in Tibet, and in recent times the use of these has increased among the painters now living in India and Nepal. The main reason for this increase is the exorbitant price of gold. Nowadays it is impractical to use gold lavishly in a thangka unless it is specifically requested by the patron, and a few painters are even willing to do paintings that incorporate no real gold at all. They use powdered brass alone for even the minimal "golden" outlines and finishing details. Nevertheless, every painter whom we knew seemed to prefer using real gold, and they were happy if the patron set aside a certain sum just to cover its cost.

Special Binders for Gold

Even though gold in thangka painting was almost invariably applied in a size medium, for painting other objects Tibetan artists also used special binders for gold. Peeling and cracking were common problems when gold was applied as "cold gilt" (i.e. in a size medium) to the faces of metal statues. Therefore for these and other metal objects, many painters employed a glutinous extract from flax seeds as an initial coating to the metal and as a binder for gold. This extract was made by merely soaking the flax seeds in a little hot water - a simple procedure compared with the extraction of another special binder, linseed oil, from the same seeds.

Linseed oil (zar khu 'i snum rtsi) was a drying oil initially produced by pressing oil from flax seeds (zar ma'i 'bru).55 A traditional method for preparing linseed oil was described by Bo-dong Pal)-chen in the 15th century, and the same method continued to be used down to the present century. 56 Here we may summarize the traditional preparation of linseed oil by paraphrasing Bo-dong Pal)-chen's account.

The production of linseed oil, he says, began with the cooking of the flax seeds and then kneading them into a dough-like mass. This was left to dry, and then it was thoroughly pounded. When the husks of the flax seeds had reached the consistency of 'ba' cha (a fodder commonly made in Tibet from pressed seeds or grains), the worker put the beaten seeds into a wooden basin and moistened them with water that was as hot as the hands could bear. Then he extracted the crude oil (mar khu) by squeezing the warm paste with his hands. The oil was next allowed to clarify, and then it had to be refined by heating over a low fire for three days.

Sesame oil too was prepared by crushing, heating and squeezing the seeds. Then it had to be refined over a low fire. First the partially clarified oil was poured into an iron, copper or bronze pot. The worker then set this pot on a round stove that was made from clay, with holes for the addition of fuel and the removal of ashes. During heating the flames could not be allowed to burn so high that they reached out of either the front or back openings of the stove. Also, it was good to keep [thepot?] encased in mud [to reduce the chances of an accidental fire?]. Dried and winnowed dung pellets of sheep or goats made a good fuel because their fire burned low and without much smoke. During heating the flames of the fire should just barely touch the pot.

After heating the oil for one day it was best to add a small amount of spas-smug resin and borax (tsha la). Finally, when the oil had been heated over a low fire for the full three days, it was filtered through a clean cotton cloth and then stored in some container with a cap or lid. This concludes Bo-dong Pal)-chen's account.

Western artists would call oil refined in the above way "boiled oiL" It is also a "drying oil," which means that when it is applied in thin coats and left to dry it forms a clear, hard solid through oxidation and polymerization. The addition of certain metallic or chemical substances to boiled linseed oil greatly shortens its drying period, and this was probably the reason for the addition of borax as described by Bo-dong Pal)- chen.57 Some Tibetan artisans added the lead mineral thel-gdan, which would definitely act as a catalyst in drying.58 In addition to its use as a medium in painting, refined oil can be applied alone as a waterproof coating like varnish, and if resin is added in substantial amounts to boiled linseed oil, a true varnish is the result.

Another special binder used for gold was a glutinous solution made from roasted wheat (gro tshig). This binder was not used in thangka painting, but it was employed for instance by scribes doing gold lettering and as a binder for other inks. L. S. Dagyab described this binder as having been prepared from "fried" (i.e. roasted) grains of wheat. Once the grains had been roasted to a black colour they were "poured into a container of hot water but not boiled any further."59

Some painters applied "cold gilt" to the faces of statues using ordinary size as the binder, but in this case it was essential to prepare the surface in a special way. The painter Wangdrak for instance began by peeling a small white radish, which he first used to rubthe area of metal that was. to receive the gold paint. Next he chopped the radish into a pulp, and squeezed out its juice through a rag. To this juice he added small amounts of sugar and hide glue, and then applied one coat of this mixture to the metal. The next step was to apply a coat of "gold-base" - a paint made by mixing yellow ochre (or nowadays white with a little yellow) with size solution in the normal proportions for paint. Finally the powdered gold itself was applied. But even though here ordinary size was the binder, it was to be used in a very dilute solution containing just enough size to hold the gold in place. (Wangdrak believed that the binder in the ochre undercoat helped to hold the gold.) This technique was considered equal to the use of flax-seed binder for producing a strong gold paint over metal.